Effect of different standoff distance and driving current on transducer during ultrasonic cavitation peening

- The response of the transducer to cavitation bubbles in small gaps is studied during ultrasonic cavitation peening.
- The resonance frequency almost keeps stable at a fixed standoff without the influence of the driving current.
- The electrical impedance of the transducer almost maintains unchanged with high driving currents.

Ultrasonic cavitation peening is a potential technique in the field of mechanical surface treatment. Owing to the collapses of cavitation bubbles, it generates high impacting pressures on peening surface whose reliability will be enhanced. However, the cavitation phenomena between horn tip and workpiece surface are highly nonlinear so that the piezoelectric transducer is subjected to tough operational condition. In this work, the influences of different standoff distances and vibration amplitudes on the transducer electrical impedance and resonance frequency are investigated both theoretically and experimentally. The results indicate that the changing of the resonance frequency is small at a standoff distance of ∼1 mm. The electrical impedance of the transducer remains stable for high driving current.